In the above-mentioned co-pending application, a method of manufacturing barriers, and barriers themselves, were described, which utilized cut-up pieces of recycled vehicle tires to form building block members. In this earlier application, the cut-up tire material was placed in a cage which was then placed in a mold box with clearance around the outside edges of the cage for the admission of liquid latex material. The liquid latex material was supplied to the gap surrounding the cage and was allowed to harden to form a barrier which could be then used for a road barrier or the like. The barrier of this earlier application included latex material only in the outer layers around the block of material that was formed, with the interior consisting essentially of only the cut-up vehicle tire parts. This arrangement of my prior application was very well suited for certain applications, especially for the making of large barrier pieces of the type described in that application, weighing up to 1800 pounds or so.
In commercial operations for recycling vehicle tires, there is normally used a multi-stage process, including a first stage where the tires are cut into pieces about one inch by six inches in size, followed by a second shredding or cutting stage wherein the tire parts are cut into pieces with a maximum size of three inches, followed by a third stage with a maximum size of one inch, a fourth stage with a maximum size of one-half inch by one-half inch, a fifth stage with a size of about one-quarter inch maximum size, and two or three further stages that eventually reduce the tires to very small powder like particles. Depending upon the nature of the use of this recycled tire product, the shredding to the various smaller and smaller dimensions is required. For example, in most processes for making products from recycled tires, the shredding to a sixth to eighth stage with particles smaller than a quarter inch maximum are required. According to one aspect of the present invention, it is provided to utilize recycled tire pieces which have only been shredded to the third or fourth stage to a maximum size of about one-half inch. Thus, the recycling process for providing these maximally sized one-half by one-half inch tire pieces is substantially more economical than would be case if further shredding stages were required.
An object of the present invention is to improve on the arrangement of my earlier application by providing a more commercially viable way of using recycled vehicle tires to make building block members. Another object of the present invention is to provide improved apparatus and methods of manufacture which facilitate a precise control of the density of the building blocks to be formed. Another object of the present invention is to provide improved apparatus and methods which facilitate high quantity mass production with reliable repeatability of building member products being made.
Another object is to provide apparatus and method of manufacture which accommodate use of vehicle tire pieces that are first cut into pieces that are of a size of one-half inch by one-half inch or smaller, thereby obviating the need for yet further shredding or cutting steps on the tire parts.
Another object of the invention is to provide improved building block member products from recycled vehicle tires.
It is contemplated that the improved building block member products can be used for land erosion control, bank stabilization control, temporary flood control, construction of temporary dams for work under otherwise relatively shallow water, such as boat ramp constructions and the like, as road barriers, as temporary protective shields for detonation of explosions, as firing range backstops, and the like. The improved building block member products of the invention are especially suited for in ground and underwater usage as the completed and sealed block members, described herein, do not permit "leaching" of the material making up the vehicle tire parts included in the block members. It is another object to have a process and resultant block member products which can be made sufficiently dense to sink in water to thereby facilitate underwater anchoring thereof.
The objects of the present invention are obtained according to preferred embodiments of the invention by providing that the recycled tire pieces are first mixed with liquid latex material to form an uncured mixture with the liquid latex material substantially coating all of the tire parts, subsequently pouring the uncured mixture into a mold form to a predetermined level and then applying a pressure to the uncured mixture in the mold form to compress the mixture to a predetermined compressed building block member size where it is cured under pressure. With this arrangement, advantage is, taken of the fact that the unpressurized uncured mixture can be easily mixed, and then the pressurizing of this uncured mixture in a mold provides for a rather rapid curing of the mixture to form the composite solid building block member. Subsequently to a predetermined amount of curing so that the building block member is solidly self-sustaining, it is removed from the mold and, in preferred embodiments, is coated with a latex rubber sealer on the outside which dries very fast and forms a finished surface over the building member. Building block members produced according to this process are relatively homogenous throughout their cross-section and their density can be controlled by the compression step so as to provide different density building block members for different purposes. For example, building block members to be used for dike control purposes can be compressed to a higher specific density than building members to be used as highway crash barrier members.
According to certain preferred embodiments of the present invention, a multi-step compression of the uncured mixture takes place at the mold form so as to facilitate manufacture of relatively large building members with substantially uniform density. According to this preferred method of the invention, the uncured mixture of liquid latex material and tire parts is placed into a mold form to a predetermined level, a first predetermined pressure is then applied to this uncured mixture in the form to compress the same to a first precompressed level, subsequently the form is again filled to the predetermined level with further uncured mixture on top of the precompressed level layer, and a second pressure is applied to the newly added uncured mixture to compress the entire mixture in the mold to a desired final configuration. This second compression is done at a substantially higher pressure than the first precompression so that the first precompressed level layer is further compressed to the final desired density of the building member being made. This multi-stage compression of the mixture to form the completed building block facilitates a reliable, repeatable manufacturing process. It also facilitates adjustment of the compression level of the material to thereby form different density building blocks for different purposes.
In especially preferred embodiments, the building blocks formed according to the invention are of a regular polygon shape and include protrusions and recesses which are positioned to mate with corresponding recesses and protrusions in similar building blocks to form multiblock constructions. These recesses and protrusions at the exterior sides of the building block are formed at respective opposite sides of the building block by the simple means of configuring the mold box or form. Further through apertures for anchor bolts, etc. are provided in the building blocks by the simple expedient of utilizing a rod in the mold form for defining the through apertures. In especially preferred embodiments, the through apertures are located centrally of the mating recesses and protrusions on the building block.
According to certain preferred embodiments of the invention, the mixing of the liquid latex material and the shredded vehicle tire parts is accomplished by a conventional small-batch cement mixer, for example, a portable cement mixer of the type that typically mixes one-third yard batches of cement. In a preferred practical embodiment of the invention, 111 pounds of recycled tire pieces, cut to sizes of approximately one-half inch by one-half inch or smaller, are mixed with five quarts of latex material which weighs approximately eight and a quarter pounds per gallon. This mixture provides for a substantially complete uniform coating of the shredded tire parts so that when the uncured mixture is later subjected to the precompression and ultimate final compression to form the final building block configuration, a homogenous strong block of material results. Since the uncured mixture of the liquid latex material and shredded vehicle tire parts does not set up or cure very quickly to a solid when it is not under pressure, as is the case when it is being mixed in a drum-type cement mixer of the type mentioned, there is sufficient time to facilitate the mixing of a batch and of the two-step supply, precompression and further supply and final compression in the mold form. This single batch of 111 pounds of shredded tire parts and five quarts of latex results in a finished rectangular block which is two feet long, one foot high and one foot wide and weighs about 120 pounds.
In other preferred embodiments of the invention, the mixing of the liquid latex material and the shredded vehicle tire parts is accomplished by using rotating helical auger which simultaneously mixes and conveys the tire parts and liquid latex material sprayed thereon as it is being conveyed, and supplies the same to the mold form. This auger arrangement has the advantage of providing for essentially continuous supply and mixing of the uncured mixture, for sequential supply to multiple molding forms to facilitate mass production of building members.
In especially preferred embodiments, a hydraulic cylinder and ram attachment to one side of the mold serving as a presser plate is provided for applying the compression forces to the uncured mixture in the mold form. Thus, in a simple manner, the cover or presser plate of the mold form can be forced down by hydraulic pressure on the presupply of uncured mixture at the bottom of the mold form. The cover presser plate is then lifted by the hydraulic ram, the mold form is again filled to a predetermined level, and then the final compression forces are applied by the hydraulic ram and cover press plate.
According to especially preferred embodiments, the system for supplying the uncured material to the form, the hydraulic ram system for compressing the uncured mixture in the form, and the removal of the partially cured compressed building block members from the form are controlled and timed by a computer control system so as to assure consistent repeatability of building block member products to be formed. When it is desired to change the specific density of the building members to be formed, appropriate adjustments are made to the computer control system that controls the pressurizing forces on the hydraulic ram. Furthermore, the system can be calibrated in a simple manner according to the invention by initiating test runs with test building block member products being made, and then recording the positions of the hydraulic ram and the positions of the layers of uncured material before and after compression stages, which information can be stored and repeated once the desired characteristics of a building block member product are obtained. In this manner, an approximation of the density of the building member product can be precalculated, which will give a good approximation of the level of uncured material to be supplied at each of the compression stages in the mold form, as well as the pressure forces and movement of the hydraulic ram desired to reach the desired building member block side, to form initial test block members. Once optimum building block members have been achieved by checking and adjusting to calibrate the system, the control system can use these calibrated/determined values to control continuous future operations.
Such a control system is also very adaptable to changing block densities and to accommodate to different characteristics of the batch of uncured mixture which could vary a small amount depending upon the nature of the tires that have been utilized for the tire pieces that are being mixed therewith.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.